It is known that a person providing themselves, or others, with a medicament regimen may require more than one medicament as part of that regimen. For example many of those having diabetes take a combination of slow and fast acting types of insulin. It is important that the different forms of medicament do not become confused and that the patient does not receive the incorrect medicament. It is thus advantageous that different forms of medicament are provided in medicament cartridges that can readily be distinguished.
However, in the manufacture of medicament cartridges, it is desirable, in order that advantage may be taken of economies of scale that as few different manufacturing steps as possible exist as between medicament cartridges containing different medicaments.
A number of solutions to this problem are already known. For example, in U.S. Pat. No. 6,126,646 an adaptor top for fitting to a medicament cartridge is disclosed. The adaptor top has a depending skirt, the skirt being provided with an internally directed, circumferentially extending bead. The bead in use is seated beneath and against a metal cap of the medicament cartridge. In order to be placed over the cap the skirt is made very flexible or provided with a number of longitudinally extending slits. To prevent the skirt from being removed, a ring is placed over the skirt to prevent the beaded portion of the skirt from coming loose. However, should the ring in use become loose or inadvertently be dislodged, the adaptor top may easily or inadvertently become separated from the medicament cartridge.
The present invention provides a further solution to the problem of balancing the requirements presented above.